In order to obtain higher ground surface quality of silicon wafers, it is essential to better understand the grinding mechanism. This study investigates the phase transformations in ground silicon wafer surface with the aid of Raman microspectroscopy. On the surface ground by #325 grinding wheel, the characteristic Raman peak of pristine Si (Si-I) is predominant and very small amount amorphous silicon (α-Si) is observed. It shows that short-range disorder or residual strains in the Si lattice are not caused, the material was removed by brittle mode. But the Raman spectra of surface ground by #600 and #2000 wheel demonstrate the presence of the α-Si and high-pressure phases (Si-III and Si-XII). It is confirmed that the Si momentarily exists in the metallic phase Si-II during grinding process. The Si-II is ductile and easily removed by ductile mode. The transformed phases of all ground wafers disappear after chemical etching. In general, the material can be removed by ductile or brittle mode. Which mode dominates is determined by the grinding condition.